Sad times: Uggie, centre, with two of his trainer's other pets, Gordo, left and Popeye shortly before the announcement of his retirement

No wonder they look so doggone miserable. Just as Uggie the Jack Russell has become a Hollywood star thanks to his antics in silent movie The Artist, his film career is over.The ten-year-old has a mystery illness which means he is to be retired after an appearance at the Oscars this month.Uggie is expected to open the show alongside host Billy Crystal.

Top dog: Uggie relaxes by the pool at the Andaz Hotel in Hollywood. He will retire later this month

‘He is suffering from a shaking syndrome,’ said trainer Omar Von Muller, 49. ‘We’ve spent thousands trying to figure out what is causing it but the experts don’t really know. All the vets can tell us, after all the scans and tests, is that it is neurological and he is not suffering.’‘He started shaking shortly before The Artist began filming in November 2010. It comes and goes and, ironically, it is worse when he’s relaxed. When we were filming you could hardly notice it.’While it is not unusual for Jack Russells to shiver, his trainer described the symptoms as ‘abnormal’.

Stars: Jean Dujardin as George Valentin with canine actor Jack Russell Uggie, and right, with an Oscar

Uggie the dog who starred in the film The Artist is suffering from a debilitating shaking syndrome ithat has cut short his career

‘This is beyond what is normal for the breed but all the vets can tell us, after all the scans and tests, is that it is neurological and he is not suffering.’Uggie has become one of the biggest showbusiness stories of the year and now has his own Twitter page following his life at red-carpet events and on TV shows, including a recent guest spot on The Graham Norton Show.